5.0GTA

please tell me i'm not losing my mind. I keep counting 9-bolts on my differential. My buddies dont believe me and say they've never heard of a 9-bolt. Am I correct when i tell them that its very rare and only used on the 'top of the line' cars like the GTA, IROC, and Formula 350? And how come GM used a 9-bolt on their best cars instead of a 10 or 12?

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1988 Pontiac GTA 5.0 TPI
*FOR SALE* $4,000 obo
Mods: K&N Filter, Hypertech Air Foil, Hypertech Perf. Chip, 2.5in Flowmaster Muffler, Catco Hi-flow Cat

Maryland Int. Speedway Bracket Racing Trophy Winner

Best ET-15.32@88mph 2.077 60-ft.

Kills
94 Probe GT, 95 Mustang GT, 96 Impala SS, 85 Thunderbird 5.0, 95 Accord V6, 98 Integra VTEC, 70 Chevelle Malibu, CRX

1979 Pontiac Firebird
301/2-bbl automatic
Dog slow, flowmaster true duals
Best ET-break out the hour glass

camaro1j

iTrader: (1)

Yes, you are right. I had one on my car until I bought a 9" rearend.

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www.geocities.com/camaro1j/myz28.html


406
accel supper ram
6000 rpm Hyd roller cam
afr heads
spohn torque arm and crossmember
t-56 trans, [wier racing bellhousing and hydrolic throwout bearing]
9" ME rearend 3.91 Gears

88 427 Camaro

GM used them as the high performance option from 85-90. They have 9 bolts on the rear cover and 8 bolts on the ring gear (10 bolts have 10 bolts on the cover and 10 bolts on the ring gear). The 9 bolt uses cones (instead of clutches) and has 4 pinion gears (aka spider gears) and 2 side gears which make it a lot stronger than the 10 bolts 2 and 2.

A lot of people don't like them because parts are hard to find and are expensive, but that is about to change as I am finishing up the final details of making parts readily available.

Miles

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88 427 Camaro
12.18 @ 113mph 1.75 60ft
Currently installing 3.73's into my 9 bolt (YES,it is a 9 bolt & YES they are 3.73's, not 3.70. 4.11's to follow soon )
www.koolmeister.com

AlkyIROC

A few more things to add..

A 9 bolt uses a 7.75" ring gear. The 10 bolt uses a 7.5 or 7.625 ring rear.
The 10 bolt holds the axles in with c-clips. The 9 bolt bolts the axles on from the outside like a 9"

The only thing these 2 diffs have in common is the external mounts. Nothing internal is interchangable.

Oh and the 9 bolt is refered to as an Australian Borg Warner differential.

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Follow my racing progress on Stephen's racing page
and check out the race car

87 IROC-Z SuperPro ET Bracket Race Car
461 naturally aspirated Big Block

Best ET on a time slip: 11.242 altitude corrected to 10.69
Best MPH on a time slip: 121.52 altitude corrected to 127.76
Altitude corrected rear wheel HP based on power to weight ratio: 504.5
Best 60 foot: 1.546

Racing at 3500 feet elevation but most race days it's over 5000 feet density altitude!
Member of the Calgary Drag Racing Association

87 IROC bracket car, 91 454SS daily driver, 95 Homebuilt Harley

[This message has been edited by Stephen 87 IROC (edited May 30, 2001).]

5.0GTA

THanks guys! thats enough info to prove my friends wrong

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1988 Pontiac GTA 5.0 TPI
*FOR SALE* $4,000 obo
Mods: K&N Filter, Hypertech Air Foil, Hypertech Perf. Chip, 2.5in Flowmaster Muffler, Catco Hi-flow Cat

Maryland Int. Speedway Bracket Racing Trophy Winner

Best ET-15.32@88mph 2.077 60-ft.

Kills
94 Probe GT, 95 Mustang GT, 96 Impala SS, 85 Thunderbird 5.0, 95 Accord V6, 98 Integra VTEC, 70 Chevelle Malibu, CRX

1979 Pontiac Firebird
301/2-bbl automatic
Dog slow, flowmaster true duals
Best ET-break out the hour glass

super83Z

will you be able to have a kit to put 3-series gears in a 2-series rear?

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I WOULD RATHER PUSH A CAMARO THAN DRIVE AN IMPORT

1983Z28 350w/ edelbrock performer RPM power package , dynomax shorty headers, 700R-4 with shift kit, 750cfm carb, edelbrock 3" exhaust system, ASCD SS hood, 16" IROC rims.

future mods:
completely done over suspension, black paint with flames, Hurst shifter, dakota digital gauge package, procharger supercharger.

88 427 Camaro

Because this gear manufacturer does not recommend using a spacer, I probably won't, but it can be done. I will have new series 3 carriers available though.

Miles

------------------
88 427 Camaro
12.18 @ 113mph 1.75 60ft
Currently installing 3.73's into my 9 bolt (YES,it is a 9 bolt & YES they are 3.73's, not 3.70. 4.11's to follow soon )
www.koolmeister.com

drain89

iTrader: (10)

Miles, Are you gonna post the details on this board?

branz28

yea for real Miles, ya gotta let us know man. Any idea of how soon we'll know?

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89 IROC-Z 350 TPI

-Flowmaster Catback
-Performance Resource Chip
-700R4 (Rebuilt) Too much done to actually list
-K&N Airfilters
-Ported Plenum
-2.77 Gears (not much to brag about but eh, its there)
-MSD 8.5 mm plug wires
-Gutted cat
-!AIR
-Gutted Air Boxes

88 427 Camaro

I will post all the info on the board once everything is finalized. This has been in the works for way too long now, but it looks like it is real close now.

I do have the 3.73 (not the 3.70) gear installed in my car, but have only driven it in the driveway as I am still putting the car back together from the paint job.

I am hoping (again) that parts will be shipped this week or next.

Miles

------------------
88 427 Camaro
12.18 @ 113mph 1.75 60ft
Currently installing 3.73's into my 9 bolt (YES,it is a 9 bolt & YES they are 3.73's, not 3.70. 4.11's to follow soon )
www.koolmeister.com